Combined influence of Be and Ca on improving the high-temperature oxidation resistance of the magnesium alloy Mg-9Al-1Zn

• DOI: 10.1016/j.corsci.2017.03.023
• Publication Date: 2017-03-28T12:01:24Z
• Authors: Qiyang Tan; Ning Mo; Bin Jiang; Fusheng Pan; Andrej Atrens; Ming-Xing Zhang
• Keywords: Thermal Stability; High-Temperature Corrosion

Abstract The present work showed that the oxidation resistance of Mg-9Al-1Zn at elevated temperatures was improved by combined alloying with Be and Ca. AZ91 alloyed with 20 ppm (wt) Be and 0.5 wt.% Ca had higher oxidization resistance than that of AZ91 containing 60 ppm (wt) Be. The improved oxidation resistance was attributed to (a) the formation of a Be-reinforced compact CaO-MgO composite layer on the alloy surface, and (b) suppressing the grain boundary evaporation of Mg by (i) the elimination of Mg-Al eutectic micro-constituent, and (ii) the increase in thermal stability of the β-Mg17Al12 due to the Ca alloying.